The formation of narrow nanocluster bands in Ge-implanted SiO 2-layers

Abstract

The paper describes the formation of Ge nanocrystals in thin thermally grown SiO 2-layers ( d ox⩽100 nm) using implantation of 10 15–2×10 16 Ge +/cm 2 and subsequent annealing. Although the implanted Ge depth profile is distributed over almost the whole SiO 2 layer, a very narrow band (typical width 5 nm) of Ge nanoclusters very close but well-separated to the Si/SiO 2-interface is formed by self-organization under specified annealing conditions. A possible mechanisms for this self-organization process is discussed including nucleation phenomena, Ostwald ripening and defect-stimulated interface processes. Simple MOS-structures were prepared and the effect of charge storage inside the clusters has been derived from C– V characteristics.